Lime slurry Viscosity

I’m working on a design for a separating tank in a lime slaking system and have really hard time finding viscosity data that would make sense. I’m looking at nom 25% by wt lime slurry at 185F.
I’ve contacted a number of pump suppliers, but they don’t seem to have anything exact. For now I’m using a ballpark figure of ~100cPs and see if the lab tests we are planning to do will give me something different.


The viscosity of hydroxide slurry can vary greatly from lime to lime as well as process conditions. Certain changes in the hydration conditions or impurities in the lime will increase the viscosity of the slurry, thus affecting settling time.

Often times, the viscosity increases at slaking temperatures of 80°C (~176 F) and above. The relationship of viscosity, particle size, specific surface and settling rate is not currently completely researched. In general, it is presumed that the higher viscosity means a smaller particle size of hydrate, greater specific surface and slower settling rate. Variations of the viscosity of hydrated lime slurry have been reported between a range of 45-700 centipoise - so lab testing is definitely worthwhile for your specific application.

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